Timing Treatments to the Phenology of Root Carbohydrate Reserves to Control Woody Invasive Plants (Richburg doctoral dissertation 2005)




In the Northeast, land managers are combating the deleterious effects that invasive plants have on other species and natural communities with attempts to remove them or substantially reduce their density. Control methods vary depending on the target species’ growth form, the extent of the invasion, and other species and resources at the site. Mechanical treatment, prescribed fire, hand-pulling, and application of herbicides, alone or in combination, have all been used to attempt control.

Woody invasive plants are often difficult to eliminate due to their ability to sprout from stems, stumps, and roots. Successful control of these species requires understanding temporal variations in their below-ground resources. Total non-structural carbohydrate (TNC) reserves in the roots of woody species support growth following disturbance and generally follow an annual cycle of depletion and replenishment. This study evaluates the effectiveness of treatments when applied during periods of decreased TNC reserves.

Treatments were applied to seven invasive shrubs (Cornus racemosaRhamnus catharticaRosa multifloraBerberis thunbergiiLonicera morrowiiSmilax rotundifolia, and Cytisus scoparius) at three different sites in Massachusetts and New York. Treatments included cutting and/or burning, applied singly or in combination, in either the dormant or growing seasons.

TNC were depleted following all treatments. Dormant-season-treated plants, whether cut or burned, sprouted and replenished their reserves within the following growing season. For growing-season-treated plants TNC remained depleted longer, with a greater effect on plants that received more treatments. For most species studied, TNC recovered to pre-treatment levels by the end of one growing season without treatment.

Sprout growth was influenced by the extent of carbohydrate reserves present before treatment. Biomass and heights of sprouts were significantly lower in growing- season-treated plants than those treated in the dormant season, even when data were adjusted for different lengths of recovery time.

All treatments reduced the cover of the target invasive shrub. As the plants sprouted, they regained some of their initial cover and are expected to dominate without further treatment. Timing treatments to the cycle of TNC can increase the effectiveness of control methods, although repeated treatments may be necessary for several years.

Characteristics of Fuel Beds Invaded by Smilax rotundifolia (Ohman MS thesis 2006)




Invasion of grasslands by woody shrubs can alter existing fire regimes and give rise to problem fire behavior. Invaded areas are likely to burn less often but with more intensity. Abandoned pastures on Naushon Island, Massachusetts (USA) which have been invaded by the woody vine Smilax rotundifolia follow this pattern. I evaluated the usefulness of standard and custom fuel models for predicting fire behavior observed in a 0.5-acre (0.2-ha) experimental burn. Custom fuel model development required characterizing fuel load and fuel bed depth of the experimental burn plot – a task complicated a dense mat of vines with 100 % cover to a height of 3 to 6 ft (1 to 2 m). This was done by measuring the height of fuel beds, estimating 3-dimensional cover by modified point-intercept sampling, and harvesting live vines and leaves and dead woody and non-woody litter and vines from 1 m2 cubes. From these data, I developed regression equations to estimate fuel load using fuel bed depth.

The Modern and Historic Fire Regimes of Central Martha's Vineyard, Massachusetts (Mouw 2002)


Tables and Figures.pdf>


The goals of this project were to determine how fire and vegetation have interacted in the past 150 years in the central Martha’s Vineyard, Massachusetts woodlands, and to use this information to determine what management actions could be taken to reduce both the current and future fire danger while protecting unique plant and animal communities. Data were collected from intensive and extensive vegetation sampling, as well as from the interpretation of aerial photos. Two fire regimes were defined for the area: the late historic (1850-1955) and the modern (1955- present day). Data were collected on Manuel F. Correllus State Forest (MFCSF) which comprises 5,190 acres (2,100ha) of scrub oak (Quercus ilicifolia), oak woodland (Q. alba, Q.stellata, and Q. velutina), pitch pine (Pinus rigida) forest, and conifer plantation (primarily Pinus strobus, P. resinosa, and Picea glauca) vegetation in the center of the Island. The vegetation of the Forest has been subjected to frequent wildfires for as long as records are available and was probably burned before the arrival of Europeans in the early 17th century. Using the data collected, the stands of MFCSF were grouped into six vegetation types, and six fuel types. Six custom fuel models, which are assemblies of vegetation structure data that are used by fire behavior simulations to predict fire behavior, were then created from these six fuel types. Using the fire behavior simulators, BEHAVE and FARSITE, potential fire behavior on the Forest was then evaluated.

Characterizing Canopy Fuels as They Affect Fire Behavior in Pitch Pine

Master's Thesis by Matthew Duveneck FEBUARY 2005


Fire managers in the Northeast are increasingly concerned about crown fire development in pitch pine (Pinus rigida) P. Mill. Increased awareness of eastern crown fire problems has led to increased interest in predicting the development and behavior of crown fires in pitch pine. Models developed in the western United States exist to predict crown fire behavior. Managers in the Northeast, however, have relied on western data to predict crown fire behavior in pitch pine stands. Pitch pine-specific inputs to these models, most notably canopy bulk density (CBD), have not been available to northeastern fire managers. The objective of this study is to add pitch pine crown characteristics to the body of data on canopy fuel characteristics. Following destructive sampling of 31 pitch pine trees in Montague and on Martha’s Vineyard, Massachusetts, I developed predictive equations that will enable fire managers to predict CBD in pitch pine based on the indirect variable diameter at breast height (r2>0.93). To demonstrate the application of the predictive equations, I calculated the wind speed needed to sustain an active crown fire in a treated and an untreated pitch pine stand in Montague. The results indicate that CBD, calculated with the equations I derived, can be manipulated to reduce the threat of catastrophic crown fire.

Ecological Restoration of Fire-Maintained Oak Woodlands in Massachusetts (Hawthorne MS thesis 2004)


MAY 2004


This study describes the results of a factorial experiment involving three levels of overstory thinning (none, moderate, heavy) and two levels of prescribed burning (no burn, burn) in three replicated blocks of upland oak forest in Pelham, Massachusetts to reproduce qualities of the fire-maintained oak woodlands that are thought to have existed in southern New England prior to European settlement. The primary aspects studied were overstory structure, soft mast (berry) production, and understory openness. A reference site in Worcester, MA exhibits an open understory maintained by frequent burning and supports a unique natural community of flora and fauna. Overstory thinning was completed in January 2001, and understory burning in June 2001. Two growing seasons after treatments, burning reduced the cover of understory shrubs (p=0.0002). There was a significant interaction (p=0.011) between the treatments with regards to tree species in the understory. Overall, thinning increased the cover of tree species in the understory (p=0.002), and burning decreased the cover of tree species for all but the moderate thinning treatment (p=0.04). The number of understory species browsed by wildlife was increased by both the thinning (p<0.0001) and burning (p=0.026) treatments. Neither treatment significantly affected overall species diversity of vegetation. Thinning increased production of soft mast (p=0.001) and increased available light to the shrub-level understory (p<0.0001). Stem density, flower production, and berry production of Vaccinium angustifolium were highly correlated with available light (p<0.0001). Prescribed burning increased understory visibility in the year following application (p=0.008). Horizontal foliar density (HFD) increased linearly with distance (p<0.001) and decreased with height above ground (p<0.001). The combined results suggest that the combination of overstory thinning and understory burning is a promising method to create woodland openings that meet wildlife, aesthetic, and recreation goals for public and private landowners, while restoring a rare natural community to the Massachusetts landscape.

The estimation of burn severity using satellite imagery in a temperate deciduous forest.

New methods for evaluating burn severity across broad spatial extents, using satellite imagery, have enabled new opportunities for wildland fire managers and researchers.  While numerous studies have calibrated burn severity for forest types of the western United States, comparatively little research has been conducted in forest types of eastern US, where seasonality modulates wildfire occurrence and reflectance patterns of vegetation. 

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Islands of Pine: Future Climate Scenarios in the NJ Pinelands using the LANDIS-II Forest Landscape Disturbance and Succession Model

Assessing forest resilience to disturbances including climate change is an important aspect of adaptive management. Climate change impacts on fire and forest composition in the Pinelands of New Jersey have not been assessed to date and the prospect of major shifts in forest composition present challenges to the mission of the Pinelands National Reserve to preserve the ecological integrity of the Pinelands.

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Landscape Disturbance and Succession Modeling in the Pinelands of New Jersey using LANDIS-II: The Implications of Human Influence on Fire and Forest Composition

Coupled human-natural systems present complex relationships between human influence and ecosystem response and services. The Pinelands of New Jersey represent a highly human influenced system noted for its fire regime which helps maintain pinelands cover and halt succession from pine to oak forest composition.

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